Branched-chain amino acid metabolism in rat muscle: abnormal regulation in acidosis

Journal Article · Mon Jun 01 00:00:00 EDT 1987 · Am. J. Physiol.; (United States)

OSTI ID:6766446

May, R C; Hara, Y; Kelly, R A; Block, K P; Buse, M G; Mitch, W E

Branched-chain amino acid (BCAA) metabolism is frequently abnormal in pathological conditions accompanied by chronic metabolic acidosis. To study how metabolic acidosis affects BCAA metabolism in muscle, rats were gavage fed a 14% protein diet with or without 4 mmol NH/sub 4/Cl x 100 g body wt/sup -1/ x day/sup -1/. Epitrochlearis muscles were incubated with L-(1-/sup 14/C)-valine and L-(1-/sup 14/C)leucine, and rates of decarboxylation, net transamination, and incorporation into muscle protein were measured. Plasma and muscle BCAA levels were lower in acidotic rats. Rates of valine and leucine decarboxylation and net transamination were higher in muscles from acidotic rats; these differences were associated with a 79% increase in the total activity of branched-chain ..cap alpha..-keto acid dehydrogenase and a 146% increase in the activated form of the enzyme. They conclude that acidosis affects the regulation of BCAA metabolism by enhancing flux through the transaminase and by directly stimulating oxidative catabolism through activation of branched-chain ..cap alpha..-keto acid dehydrogenase.

• Research Organization: Brigham and Women's Hospital, Boston, MA (USA)
• OSTI ID: 6766446
• Journal Information: Am. J. Physiol.; (United States), Vol. 252:6
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
DECARBOXYLATION
METABOLISM
MUSCLES
PHYSIOLOGY
CARBON 14 COMPOUNDS
DIET
LEUCINE
PH VALUE
RATS
VALINE
ANIMALS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
LABELLED COMPOUNDS
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
RODENTS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques